因为对话框程序中,某些特点的消息,如按键消息被Windows内部的对话框过程处理了,即基类完成了或者被发送给子控件处理,所以在对话框类中就不能捕获到按键消息
解决办法:在子类中覆盖基类的特定消息过滤响应函数.
在MFC中,用虚函数ProcessMessageFilter()来过滤或者响应菜单和对话框的特定Windows消息.
在子类中覆盖它,接管消息响应.
本例中,在CWinSunApp类中增加虚函数 ProcessMessageFilter
//覆盖基类的虚函数,接管消息
BOOL CWinSunApp::ProcessMessageFilter(int code, LPMSG lpMsg)
{// TODO: Add your specialized code here and/or call the base classif(m_hwndDlg!=NULL){if(lpMsg->message==WM_KEYDOWN)AfxMessageBox("捕获WM_KEYDOWN成功!");}return CWinApp::ProcessMessageFilter(code, lpMsg);
}WinSunApp.h
// WinSun.h : main header file for the WINSUN application
//#if !defined(AFX_WINSUN_H__025D80ED_531B_42C3_8C9F_1EB3093C7BC9__INCLUDED_)
#define AFX_WINSUN_H__025D80ED_531B_42C3_8C9F_1EB3093C7BC9__INCLUDED_#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000#ifndef __AFXWIN_H__#error include 'stdafx.h' before including this file for PCH
#endif#include "resource.h" // main symbols/
// CWinSunApp:
// See WinSun.cpp for the implementation of this class
//class CWinSunApp : public CWinApp
{
public:HWND m_hwndDlg;CWinSunApp();// Overrides// ClassWizard generated virtual function overrides//{
{AFX_VIRTUAL(CWinSunApp)public:virtual BOOL InitInstance();virtual BOOL ProcessMessageFilter(int code, LPMSG lpMsg);//}}AFX_VIRTUAL// Implementation//{
{AFX_MSG(CWinSunApp)// NOTE - the ClassWizard will add and remove member functions here.// DO NOT EDIT what you see in these blocks of generated code !//}}AFX_MSGDECLARE_MESSAGE_MAP()
};///{
{AFX_INSERT_LOCATION}}
// Microsoft Visual C++ will insert additional declarations immediately before the previous line.#endif // !defined(AFX_WINSUN_H__025D80ED_531B_42C3_8C9F_1EB3093C7BC9__INCLUDED_)
WinSunApp.cpp
// WinSun.cpp : Defines the class behaviors for the application.
//#include "stdafx.h"
#include "WinSun.h"
#include "WinSunDlg.h"#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif/
// CWinSunAppBEGIN_MESSAGE_MAP(CWinSunApp, CWinApp)//{
{AFX_MSG_MAP(CWinSunApp)// NOTE - the ClassWizard will add and remove mapping macros here.// DO NOT EDIT what you see in these blocks of generated code!//}}AFX_MSGON_COMMAND(ID_HELP, CWinApp::OnHelp)
END_MESSAGE_MAP()/
// CWinSunApp constructionCWinSunApp::CWinSunApp()
{// TODO: add construction code here,// Place all significant initialization in InitInstance
}/
// The one and only CWinSunApp objectCWinSunApp theApp;/
// CWinSunApp initializationBOOL CWinSunApp::InitInstance()
{AfxEnableControlContainer();// Standard initialization// If you are not using these features and wish to reduce the size// of your final executable, you should remove from the following// the specific initialization routines you do not need.#ifdef _AFXDLLEnable3dControls(); // Call this when using MFC in a shared DLL
#elseEnable3dControlsStatic(); // Call this when linking to MFC statically
#endifCWinSunDlg dlg;m_pMainWnd = &dlg;int nResponse = dlg.DoModal();if (nResponse == IDOK){// TODO: Place code here to handle when the dialog is // dismissed with OK}else if (nResponse == IDCANCEL){// TODO: Place code here to handle when the dialog is// dismissed with Cancel}// Since the dialog has been closed, return FALSE so that we exit the// application, rather than start the application's message pump.//将CWinSunApp类的成员变量设置为NULLm_hwndDlg =NULL;return FALSE;
}//覆盖基类的虚函数,接管消息
BOOL CWinSunApp::ProcessMessageFilter(int code, LPMSG lpMsg)
{// TODO: Add your specialized code here and/or call the base classif(m_hwndDlg!=NULL){if(lpMsg->message==WM_KEYDOWN)AfxMessageBox("捕获WM_KEYDOWN成功!");}return CWinApp::ProcessMessageFilter(code, lpMsg);
}
WinSunDlg.h
// WinSunDlg.h : header file
//#if !defined(AFX_WINSUNDLG_H__9DC85391_A9DD_4A1E_8380_6A32A3CF15EF__INCLUDED_)
#define AFX_WINSUNDLG_H__9DC85391_A9DD_4A1E_8380_6A32A3CF15EF__INCLUDED_#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000/
// CWinSunDlg dialogclass CWinSunDlg : public CDialog
{
// Construction
public:CWinSunDlg(CWnd* pParent = NULL); // standard constructor// Dialog Data//{
{AFX_DATA(CWinSunDlg)enum { IDD = IDD_WINSUN_DIALOG };// NOTE: the ClassWizard will add data members here//}}AFX_DATA// ClassWizard generated virtual function overrides//{
{AFX_VIRTUAL(CWinSunDlg)protected:virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support//}}AFX_VIRTUAL// Implementation
protected:HICON m_hIcon;// Generated message map functions//{
{AFX_MSG(CWinSunDlg)virtual BOOL OnInitDialog();afx_msg void OnSysCommand(UINT nID, LPARAM lParam);afx_msg void OnPaint();afx_msg HCURSOR OnQueryDragIcon();afx_msg void OnDestroy();//}}AFX_MSGDECLARE_MESSAGE_MAP()
};//{
{AFX_INSERT_LOCATION}}
// Microsoft Visual C++ will insert additional declarations immediately before the previous line.#endif // !defined(AFX_WINSUNDLG_H__9DC85391_A9DD_4A1E_8380_6A32A3CF15EF__INCLUDED_)
WinSunDlg.cpp
// WinSunDlg.cpp : implementation file
//#include "stdafx.h"
#include "WinSun.h"
#include "WinSunDlg.h"#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif/
// CAboutDlg dialog used for App Aboutclass CAboutDlg : public CDialog
{
public:CAboutDlg();// Dialog Data//{
{AFX_DATA(CAboutDlg)enum { IDD = IDD_ABOUTBOX };//}}AFX_DATA// ClassWizard generated virtual function overrides//{
{AFX_VIRTUAL(CAboutDlg)protected:virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support//}}AFX_VIRTUAL// Implementation
protected://{
{AFX_MSG(CAboutDlg)//}}AFX_MSGDECLARE_MESSAGE_MAP()
};CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{//{
{AFX_DATA_INIT(CAboutDlg)//}}AFX_DATA_INIT
}void CAboutDlg::DoDataExchange(CDataExchange* pDX)
{CDialog::DoDataExchange(pDX);//{
{AFX_DATA_MAP(CAboutDlg)//}}AFX_DATA_MAP
}BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)//{
{AFX_MSG_MAP(CAboutDlg)// No message handlers//}}AFX_MSG_MAP
END_MESSAGE_MAP()/
// CWinSunDlg dialogCWinSunDlg::CWinSunDlg(CWnd* pParent /*=NULL*/): CDialog(CWinSunDlg::IDD, pParent)
{//{
{AFX_DATA_INIT(CWinSunDlg)// NOTE: the ClassWizard will add member initialization here//}}AFX_DATA_INIT// Note that LoadIcon does not require a subsequent DestroyIcon in Win32m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}void CWinSunDlg::DoDataExchange(CDataExchange* pDX)
{CDialog::DoDataExchange(pDX);//{
{AFX_DATA_MAP(CWinSunDlg)// NOTE: the ClassWizard will add DDX and DDV calls here//}}AFX_DATA_MAP
}BEGIN_MESSAGE_MAP(CWinSunDlg, CDialog)//{
{AFX_MSG_MAP(CWinSunDlg)ON_WM_SYSCOMMAND()ON_WM_PAINT()ON_WM_QUERYDRAGICON()ON_WM_DESTROY()//}}AFX_MSG_MAP
END_MESSAGE_MAP()/
// CWinSunDlg message handlersBOOL CWinSunDlg::OnInitDialog()
{CDialog::OnInitDialog();// Add "About..." menu item to system menu.// IDM_ABOUTBOX must be in the system command range.ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);ASSERT(IDM_ABOUTBOX < 0xF000);CMenu* pSysMenu = GetSystemMenu(FALSE);if (pSysMenu != NULL){CString strAboutMenu;strAboutMenu.LoadString(IDS_ABOUTBOX);if (!strAboutMenu.IsEmpty()){pSysMenu->AppendMenu(MF_SEPARATOR);pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);}}// Set the icon for this dialog. The framework does this automatically// when the application's main window is not a dialogSetIcon(m_hIcon, TRUE); // Set big iconSetIcon(m_hIcon, FALSE); // Set small icon// TODO: Add extra initialization here//将对话框的句柄传递到CWinSunApp类中((CWinSunApp*)AfxGetApp())->m_hwndDlg =this->m_hWnd;return TRUE; // return TRUE unless you set the focus to a control
}void CWinSunDlg::OnSysCommand(UINT nID, LPARAM lParam)
{if ((nID & 0xFFF0) == IDM_ABOUTBOX){CAboutDlg dlgAbout;dlgAbout.DoModal();}else{CDialog::OnSysCommand(nID, lParam);}
}// If you add a minimize button to your dialog, you will need the code below
// to draw the icon. For MFC applications using the document/view model,
// this is automatically done for you by the framework.void CWinSunDlg::OnPaint()
{if (IsIconic()){CPaintDC dc(this); // device context for paintingSendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);// Center icon in client rectangleint cxIcon = GetSystemMetrics(SM_CXICON);int cyIcon = GetSystemMetrics(SM_CYICON);CRect rect;GetClientRect(&rect);int x = (rect.Width() - cxIcon + 1) / 2;int y = (rect.Height() - cyIcon + 1) / 2;// Draw the icondc.DrawIcon(x, y, m_hIcon);}else{CDialog::OnPaint();}
}// The system calls this to obtain the cursor to display while the user drags
// the minimized window.
HCURSOR CWinSunDlg::OnQueryDragIcon()
{return (HCURSOR) m_hIcon;
}void CWinSunDlg::OnDestroy()
{CDialog::OnDestroy();// TODO: Add your message handler code here//对话框窗口销毁后,将CWinSumApp类中的变量m_hwndDlg置为NULL((CWinSunApp*)AfxGetApp())->m_hwndDlg =NULL;
}
//---
//---
//---编译运行,试着按下键盘任意一个键:
//---
